Extruded elastomeric compression seals for filling expansion joints in bridges, parking decks, and the like are well known in the art. Typically, such a seal will be installed within the void between adjacent concrete slabs to absorb thermal expansion of the adjacent slabs while preventing moisture and debris from penetrating the joint.
In addition to forming a tight seal between the adjacent structures, it is important that the seal collapse in such a manner that it does not distort upwardly to protrude above the upper surfaces of the adjacent structures. When the seal protrudes upwardly from the joint, pedestrians might trip on the protrusion, or snow plows might catch the seal and damage it or disengage it from the expansion joint. Accordingly, there is a need to provide a compression seal which collapses in response to thermal expansion of the adjacent structures in a controlled manner so as not to protrude upwardly of the joint.
A further consideration in the design of such compression seals is that they provide a substantially planar upper surface acceptable for pedestrian traffic. Accordingly, many prior art seals designed to collapse downwardly upon compression, while acceptable for vehicular traffic, might be totally unsuited for pedestrian traffic since the high heels of womens' shoes can easily become caught in the depression, causing a potential pedestrian hazard.
Accordingly, there is a need to provide a compression seal which maintains a substantially planar upper surface at all points during its compression.
Several previous efforts have been made to design a seal to provide a substantially planar upper surface, but with limited success. Generally, the approach has been to provide a plurality of substantially planar upper wall sections separated by V-shaped indentations. Examples of such seals are shown in U.S. Pat. Nos. 4,098,043, 4,148,167, 3,276,336, and 4,043,693. As these seals are compressed, the V-shaped indentations separating the planar upper wall sections close. Thus, in their compressed configuration, these seals succeed in providing a continuous, substantially planar upper treadway. However, upon thermal contraction of the adjacent structures, the seal expands, causing the V-shaped indentations to open. Thus, when these seals are in a partially compressed configuration, womens' high heels can easily become lodged in the V-shaped indentations.